Manufacturing method of Ni-based single-crystal high-temperature alloy hollow blade through electron beam selective 3D printing

Abstract

The invention provides an electron beam selective 3D printing Ni-based single-crystal high-temperature alloy hollow blade manufacturing method which comprises the steps that alloy raw materials are put into a water-cooling copper crucible induction melting furnace to be smelted, a Ni-based alloy bar B2 is obtained through casting and machining, spherical Ni-based alloy powder F1 is prepared through a plasma rotating electrode method, and the Ni-based alloy powder F1 is obtained after cleaning and screening. Spherical Ni-based alloy powder F2 is obtained and loaded into an electron beam 3D printer; carrying out additive design on the hollow blade model, setting parameters of a printer, and carrying out electron beam selective 3D printing; and after printing is completed, powder is recycled, a Ni-based alloy hollow blade blank Z1 is obtained, a Ni-based alloy hollow blade blank Z2 is obtained through solid solution and aging treatment, a Ni-based alloy hollow blade Z3 is obtained through machining, and the Ni-based single-crystal hollow blade is obtained through plasma polishing treatment. The method can be used for preparing high-temperature alloy parts with complex structures and larger sizes, and has the advantages of high efficiency, good structure uniformity, high cleanliness and high yield.

Description

Technical Field

[0001] The present invention relates to the technical field of metal additive manufacturing, and in particular to a method for manufacturing a hollow blade of a Ni-based single crystal high-temperature alloy by electron beam selective 3D printing. Background Art

[0002] In modern advanced turbine engines, more than 50% of the materials are high-temperature alloys, of which Ni-based single crystal alloys account for about 40%. Ni-based single crystal alloys have excellent comprehensive properties at medium and high temperatures and are mainly used in structural components working at 850℃ to 1150℃ in the aerospace field, such as working blades, turbine disks, combustion chambers, etc. of aircraft engines. At present, Ni-based single crystal blades are mainly prepared by investment casting, but the casting method has some disadvantages, such as: (1) the water-cooled copper crucible vacuum induction melting equipment is complex to operate and expensive; (2) the casting yield is low, and problems such as impurities or large-angle skewed crystals and shrinkage are prone to occur during the casting process; (3) the casting cycle is long and the flexibility is poor. In addition, the cost of Ni-based single crystal high-temperature alloys is expensive. These factors have resulted in a high price for Ni-based single crystal blades, restricting the application of Ni-based single crystal materials in aerospace and gas turbines. Summary of the invention

[0003] According to the above-mentioned traditional casting method, when preparing Ni-based single crystal hollow blades, due to technical problems such as low yield (about 10%) and poor performance caused by impurity crystals or large-angle deflected crystals and shrinkage, a method for manufacturing Ni-based single crystal high-temperature alloy hollow blades by electron beam selection 3D printing is provided. The present invention mainly controls the whole process, adopts high-purity metal component smelting, obtains high-purity Ni-based alloy rods, prepares Ni-based alloy powder by rotating electrode method, and then further removes impurities by vacuum plasma cleaning process. After screening, high-purity Ni-based alloy powder for electron beam selection 3D printing is obtained, and then in the vacuum environment of the electron beam 3D printing equipment forming chamber, the preparation of Ni-based alloy hollow blade blanks by crystal selector mode is realized, and then after solid solution + aging treatment, machining and plasma polishing treatment, Ni-based single crystal hollow blades that meet the design requirements are finally obtained. This method can prepare high-temperature alloy parts with complex structure and large size, and has the advantages of high efficiency, good organizational uniformity, high cleanliness and high yield. The yield rate of Ni-based single crystal hollow blades (more than 90%) has been greatly improved compared with the traditional casting method (about 10%). This method is very suitable for the manufacture of high-value and complex structural parts such as Ni-based single crystal hollow blades, and has the remarkable characteristics of high efficiency, high yield rate and excellent performance.

[0004] The technical means adopted by the present invention are as follows:

[0005] A method for manufacturing a hollow blade of a Ni-based single crystal high-temperature alloy by electron beam selective 3D printing, comprising the following steps:

[0006] Step 1: Place the proportioned alloy raw materials into a water-cooled copper crucible induction melting furnace for smelting, and prepare a Ni-based alloy rod B2 through casting and machining;

[0007] Step 2: using a plasma rotating electrode method to prepare a spherical Ni-based alloy powder F1 from a Ni-based alloy rod B2;

[0008] Step 3: Wash and sieve the spherical Ni-based alloy powder F1 to obtain the spherical Ni-based alloy powder F2, and load the spherical Ni-based alloy powder F2 into the powder storage box of the electron beam 3D printer;

[0009] Step 4: Design the hollow blade model with additive materials, set the printer parameters, and perform electron beam selected area 3D printing;

[0010] Step 5: After the electron beam selected area 3D printing is completed, the powder is recovered to obtain a Ni-based alloy hollow blade blank Z1;

[0011] Step 6: performing solid solution and aging treatment on the Ni-based alloy hollow blade blank Z1 to obtain a Ni-based alloy hollow blade blank Z2;

[0012] Step 7: machining the Ni-based alloy hollow blade blank Z2 to obtain a Ni-based alloy hollow blade Z3;

[0013] Step 8: Plasma polishing is performed on the Ni-based alloy hollow blade Z3 to obtain a Ni-based single crystal hollow blade.

[0014] Furthermore, in the step 1, the purity of the alloy raw materials is 99.999% pure metal raw materials, containing the following components in weight proportions: Cr: 2.0-4.6%; Co: 0.2-16.5%; Mo: 1.0-3.9%; W: 5.0-6.0%; Ta: 5.0-8.25%; Al: 5.5-6.0%; Re: 4.0-6.9%; Ru: 2.0-6.0%, Hf: 0.1%, and the rest is Ni.

[0015] Furthermore, in step 1, the vacuum degree is less than 10 -3 The master alloy is melted in a water-cooled copper crucible induction suspension melting furnace at 1550-1750°C for 5-15 min. The alloy composition is homogenized after 1 to 5 meltings. CaO is used to make a melt shell for casting into a Ni-based alloy rod B1. The size of the Ni-based alloy rod B1 is 71×290 mm. After machining, it is made into a Ni-based alloy rod B2 with a size of 70×285 mm and a surface roughness Ra<0.8 μm.

[0016] Furthermore, in the step 2, the plasma rotating electrode method adopts a plasma rotating electrode powder making equipment, the Ni-based alloy rod B2 is loaded into the plasma rotating electrode powder making equipment, the electrode speed is set to 16000-25000r / min, the plasma arc current is 1500-2600A, and the Ni-based alloy powder is prepared under a vacuum state. After the preparation is completed, spherical Ni-based alloy powder F1 with a particle size distribution of 50 to 175μm is obtained through screening.

[0017] Furthermore, in the step three, the Ni-based alloy powder F1 is loaded into a vacuum plasma cleaning device, a mixed gas medium of H2:Ar2=1:1 is selected, the power is set to 210-270W, and the time is 1-10 minutes to perform argon ion cleaning; after the cleaning is completed, the Ni-based alloy powder F1 is sieved to obtain a spherical Ni-based alloy powder F2 with a particle size distribution of 45 to 155 μm.

[0018] Further, in the step 4, the additive design method is: adding a 0.5-1.5 mm machining allowance to the entire exterior of the hollow blade 3D model M1 to form a 3D printed hollow blade blank part model M2, designing a spiral crystal selector structure 3D model X1 at the bottom center of the 3D printed hollow blade blank part model M2, and combining to form a 3D printed hollow blade model Y1, wherein the spiral crystal selector has a pitch of 20-35 mm, a spiral diameter of 10-30 mm, a wire diameter of 4-6 mm, a rise angle of 35-70°, and a spiral number of 1-3 turns, so that the main orientation of the obtained single crystal is in the

[001] direction; slicing the 3D printed hollow blade model Y1, with a slice layer thickness of 0.03-0.3 mm, obtaining a 3D printed hollow blade data parameter Y2, and importing the 3D printed hollow blade data parameter Y2 into an electron beam 3D printer;

[0019] The printer parameter settings include: vacuuming to ≤0.3Pa, preheating temperature parameters set to 1000~1300℃, and holding time of 30min; the part entity printing parameters are set to: electron beam current of 25~48mA, scanning speed of 5-15m / s; after printing is completed, the vacuum is naturally cooled to room temperature with the furnace.

[0020] Furthermore, in the step five, when the powder is preheated and sintered at high temperature for a long time and presents a pseudo-sintered state and forms a sintered brick, the parts are in the sintered brick. The sintered brick is transported to the electron beam powder recovery equipment, and 1 kg of Ni-based alloy powder F2 is pre-placed in the powder recovery equipment. After the equipment door is closed, the spraying is started, and the Ni-based alloy powder F2 is sprayed out from the spray gun at high pressure to spray the sintered brick, gradually breaking up the brick body to form recovered Ni-based alloy powder F3. After the spraying is completed, the Ni-based alloy hollow blade blank Z1 is taken out.

[0021] Furthermore, in the step six, the Ni-based alloy hollow blade blank Z1 is placed in a high vacuum heat treatment furnace for solution treatment and aging treatment, which specifically includes the following steps:

[0022] The pressure in the high vacuum heat treatment furnace is pumped down to 10 -3 Pa, heat treatment: starting from room temperature of 20℃, heating to 1000℃ at a heating rate of 10℃ / min, then heating to 1300±5℃ at a heating rate of 5℃ / min on the basis of 1000℃, then heating to 1350±5℃ at a heating rate of 2.5℃ / min on the basis of 1300±5℃, and keeping at 1350±5℃ for 10h~20h;

[0023] After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s; thereafter, starting from a furnace temperature of 50°C, the temperature is increased to 870-920°C at a heating rate of 10°C / min, and the temperature is kept for 12-30h. After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s. The furnace door is opened, and the Ni-based alloy hollow blade blank Z2 that has undergone solid solution and aging treatment is taken out.

[0024] Furthermore, in step seven, the machining cutting speed is 400-1600 r / min, the feed rate is 200-1200 mm / min, and the cutting width is 4-10 mm to remove the surface machining allowance.

[0025] Furthermore, in the step eight, the polishing temperature of the plasma polishing treatment is 75°C, the polishing voltage is 250-350V, the polishing time is 2-10min, and the plasma polishing treatment is performed using a plasma liquid, the plasma liquid is composed of ammonium sulfate, sodium citrate and distilled water, ammonium sulfate: sodium citrate: distilled water = (1-5): (0.5-2.5): 100; the surface roughness Ra of the Ni-based single crystal hollow blade Z4 is <0.8μm.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The present invention uses high-purity metal component smelting through full-process process control to obtain high-purity Ni-based alloy rods, and prepares Ni-based alloy powder through the rotating electrode method, and then further removes impurities through the vacuum plasma cleaning process. After screening, high-purity Ni-based alloy powder is obtained, and then in the vacuum forming chamber of the electron beam 3D printing equipment, the preparation of Ni-based alloy hollow blade blanks by the crystal selector method is realized, and then after solid solution + aging treatment, machining and plasma polishing treatment, Ni-based single crystal hollow blades that meet the requirements are obtained. This method is very suitable for the high-performance manufacturing of Ni-based single crystal hollow blades, and has the characteristics of high efficiency and high yield rate. It has broad prospects in the high-temperature and high-performance blade manufacturing in the fields of aerospace and gas turbines.

[0028] 2. The method of the present invention can prepare high-temperature alloy parts with complex structures and large sizes, and has the advantages of high efficiency, good structural uniformity, high cleanliness and high yield rate. The yield rate of Ni-based single crystal hollow blades (more than 90%) has been greatly improved compared with the traditional casting method (about 10%).

[0029] Based on the above reasons, the present invention can be widely promoted in the fields of metal additive manufacturing and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0031] Figure 1 Flow chart of the method of the present invention. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0035] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0036] Example 1

[0037] The present invention provides a method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing, and discloses a full-process manufacturing method for preparing a hollow Ni-based single crystal high-temperature alloy blade by Ni-based alloy powder and electron beam selective 3D printing. The present invention provides an additive manufacturing method for preparing a hollow Ni-based single crystal high-temperature alloy blade that is superior to a traditional casting method. It is a full-process preparation method, and a high-purity Ni-based high-temperature alloy powder is developed. A hollow Ni-based single crystal high-temperature alloy blade is prepared in an electron beam selective 3D printing device, and the yield rate (more than 90%) and high-temperature performance are greatly improved.

[0038] A method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing of the present invention comprises the following steps:

[0039] (1) Select pure metal raw materials with a purity of 99.999% and mix them according to the alloy composition. Calculated by weight percentage, the alloy chemical composition includes Cr: 2.0-4.6%; Co: 0.2-16.5%; Mo: 1.0-3.9%; W: 5.0-6.0%; Ta: 5.0-8.25%; Al: 5.5-6.0%; Re: 4.0-6.9%; Ru: 2.0-6.0%, Hf: 0.1%, and the rest is Ni.

[0040] (2) When the vacuum degree is less than 10 -3 The master alloy is melted in a water-cooled copper crucible induction suspension melting furnace at 1550-1750°C for 5-15 min, and the alloy composition is homogenized after 1-5 meltings, and a melt shell is made of CaO to cast a Ni-based alloy rod B1; the obtained Ni-based alloy rod B1 has a size of 71×290 mm, and is machined to form a Ni-based alloy rod B2 with a size of 70×285 mm and a surface roughness Ra<0.8 μm;

[0041] (3) Loading the Ni-based alloy rod B2 into a plasma rotating electrode powder making device, preparing the Ni-based alloy powder under vacuum, with an electrode speed of 16000-25000 r / min and a plasma arc current of 1500-2600 A, and obtaining spherical Ni-based alloy powder F1 with a particle size distribution of 50 to 175 μm through screening;

[0042] (4) The obtained Ni-based alloy powder F1 is loaded into a vacuum plasma cleaning device for argon ion cleaning, using a mixed gas medium of H2:Ar2=1:1, a power of 210-270 W, and a time of 1-10 minutes. After the treatment is completed, the powder is sieved to obtain a spherical Ni-based alloy powder F2 of 45-155 μm for electron beam selective melting 3D printing.

[0043] (5) loading a sufficient amount of Ni-based alloy powder F2 into a powder storage box of an electron beam 3D printer;

[0044] (6) The hollow blade three-dimensional model M1 is additively designed, and a 0.5-1.5 mm machining allowance is added to the entire exterior to form a 3D printed hollow blade blank part model M2. Then, a spiral crystal selector structure three-dimensional model X1 is designed at the bottom center of the model M2, and the three-dimensional model Y1 is combined to form a 3D printed hollow blade model Y1, wherein the spiral crystal selector has a pitch of 20-35 mm, a spiral diameter of 10-30 mm, a wire diameter of 4-6 mm, a rise angle of 35-70°, and a spiral number of 1-3 turns, so that the main orientation of the obtained single crystal is in the

[001] direction. The model Y1 is sliced, and the slice layer thickness is 0.03-0.3 mm to obtain the 3D printed hollow blade data parameter Y2, and the data parameter Y2 is imported into the electron beam 3D printer.

[0045] (7) Set up the electron beam 3D printer to carry out printing preparation and processing: evacuate to ≤0.3Pa, set the preheating temperature parameters to 1000-1300°C, and the insulation time to 30min; set the part entity printing parameters: electron beam current 25-48mA, scanning speed 5-15m / s; until printing is completed, the vacuum is naturally cooled to room temperature with the furnace.

[0046] (8) Due to the long-term preheating and sintering of the powder at high temperature, the powder has been in a pseudo-sintering state, forming a sintered brick, and the parts are in the sintered brick. The sintered brick is transported to the electron beam powder recovery equipment, and 1 kg of Ni-based alloy powder F2 is pre-placed in the equipment. The equipment is similar to a sandblasting machine. After the equipment door is closed, the spraying is started, and the Ni-based alloy powder F2 is sprayed out from the spray gun at high pressure, spraying the sintered brick, gradually breaking up the brick body to form the recovered Ni-based alloy powder F3, and finally taking out the Ni-based alloy hollow blade blank Z1.

[0047] (9) The Ni-based alloy hollow blade blank Z1 is placed in a high vacuum heat treatment furnace for solution treatment and aging treatment. The parameters are: the pressure in the furnace is pumped down to 10 -3 Pa, and then set the heat treatment temperature and time parameters, starting from 20℃ (room temperature), heating to 1000℃ at a heating rate of 10℃ / min, heating to 1300±5℃ at a heating rate of 5℃ / min, and then heating to 1350±5℃ at a heating rate of 2.5℃ / min, and keeping the temperature for 10h to 20h. After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s; then, starting from 50°C (furnace temperature), the temperature is increased to 870-920°C at a heating rate of 10°C / min, and the temperature is kept for 12-30h. After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s. The furnace door is opened, and the Ni-based alloy hollow blade blank Z2 that has undergone solid solution and aging treatment is taken out.

[0048] (10) According to the blade design drawing, the Ni-based alloy hollow blade blank Z2 subjected to solid solution and aging treatment is machined to remove the surface machining allowance. The cutting speed is 400-1600 r / min, the feed rate is 200-1200 mm / min, and the cutting width is 4-10 mm to obtain the machined Ni-based alloy hollow blade Z3.

[0049] (11) Plasma polishing is performed on the machined Ni-based alloy hollow blade Z3 to remove the defective layer on the blade surface. The plasma liquid formula is ammonium sulfate: sodium citrate: distilled water = (1-5): (0.5-2.5): 100, the polishing temperature is 75°C, the polishing voltage is 250-350V, and the polishing time is 2-10min. Finally, a Ni-based single crystal hollow blade Z4 with a surface roughness Ra < 0.8μm and a dimensional accuracy that meets the requirements of the drawing is obtained.

[0050] The present invention adopts a full-process preparation method to develop a Ni-based high-temperature alloy powder with high cleanliness, and a method for preparing a Ni-based single crystal high-temperature alloy hollow blade in an electron beam selected area 3D printing device. The prepared Ni-based single crystal alloy blade is subjected to the removal of 1mm of the surface material to finally obtain a Ni-based single crystal alloy blade. The preparation methods of Ni-based single crystal alloys at home and abroad mainly include a seed crystal method and a non-seed crystal method, and both methods adopt a casting method. The seed crystal method has a relatively complex preparation process, a large difficulty in developing seed crystals, and an extremely large difficulty in preparing large-size seed crystals. Only alloys with α in the solidified primary phase can be prepared using the seed crystal method. Therefore, there are obvious shortcomings. The non-seed crystal method has problems such as crucible material contamination of the alloy, difficulty in preparing the mold shell, and low yield. The present invention belongs to an additive manufacturing method for preparing Ni-based single crystal hollow blades, which can realize complex structures, large-size parts, high efficiency, high organizational uniformity, high cleanliness and high yield manufacturing.

[0051] Ni-based single crystal high-temperature alloys are mainly used to manufacture hot-end turbine blades for aircraft engines and gas turbines. Their temperature bearing capacity is a key technical indicator for improving engine performance, efficiency, and reliability. Ni-based single crystal high-temperature alloys have developed into fourth- and fifth-generation alloys with service temperatures exceeding 1100°C. The structure of single crystal blades is becoming more and more complex. For example, single crystal hollow blades with efficient cooling effects generally have hundreds of air film holes on the blade body. Electro-hydraulic beam or electric spark is usually used for processing. However, its processing efficiency is low and it is difficult to meet the needs of engineering mass production. In addition, after electric spark drilling, there is a remelting layer on the surface of the hole wall. The remelting layer is subsequently removed by electrolysis, but the electrolyte filling at the hole wall is insufficient, and there is a problem that the remelting layer cannot be completely removed, resulting in a single crystal hollow blade yield of less than 10%.

[0052] The present invention develops high-cleanliness Ni-based high-temperature alloy powder by adopting a full-process preparation method, and prepares a Ni-based high-temperature alloy hollow blade method in an electron beam selected area 3D printing device. The prepared Ni-based alloy blade is subjected to 1mm material removal on the surface to finally obtain a Ni-based single crystal alloy blade with a high yield (more than 90%), and the creep life under high-temperature creep performance (1100℃ / 137MPa) is 49% higher than that of traditional processed parts, and has good feasibility and application prospects for promotion and application.

[0053] Taking Ni-based single crystal high-temperature alloy hollow blades for engines and gas turbines as an example, the technology of the present invention can achieve a significant improvement in the yield and performance of Ni-based single crystal high-temperature alloy hollow blades, can greatly improve the research and development progress of new models and new products, shorten the research and development and production cycle, and reduce production costs, and has a broad market space.

[0054] Example 2

[0055] In this embodiment, a method for manufacturing a hollow blade of a Ni-based single crystal high-temperature alloy by electron beam selective 3D printing includes the following steps:

[0056] (1) Pure metal raw materials with a purity of 99.999% are selected, and the alloy components are proportioned. Calculated by weight percentage, the chemical composition of the alloy includes Cr: 3.0%; Co: 5.6%; Mo: 2.8%; W: 5.6%; Ta: 5.6%; Al: 5.6%; Re: 6.9%; Ru: 5.0%, Hf: 0.1%, and the rest is Ni.

[0057] (2) When the vacuum degree is less than 10 -3 The master alloy was melted in a water-cooled copper crucible suspension melting furnace at 1650°C for 10 min. The alloy composition was homogenized by two meltings, and a melt shell was made of CaO to cast the Ni-based alloy rod B1. The obtained Ni-based alloy rod B1 had a size of 71×290 mm and was machined to produce a Ni-based alloy rod B2 with a size of 70×285 mm and a surface roughness of Ra0.67 μm.

[0058] (3) Loading the Ni-based alloy rod B2 into a plasma rotating electrode device, preparing Ni-based alloy powder under vacuum, with an electrode speed of 18500 r / min and a plasma arc current of 2250 A, and obtaining spherical Ni-based alloy powder F1 with a particle size distribution of 50 to 175 μm through screening;

[0059] (4) The obtained Ni-based alloy powder F1 was loaded into a vacuum plasma cleaning device for argon ion cleaning, using a mixed gas medium of H2:Ar2=1:1, a power of 240 W, and a time of 3 minutes. After the treatment, the powder was sieved to obtain a spherical Ni-based alloy powder F2 of 45 to 155 μm for electron beam selective melting 3D printing.

[0060] (5) loading a sufficient amount of Ni-based alloy powder F2 into a powder storage box of an electron beam 3D printer;

[0061] (6) The hollow blade three-dimensional model M1 is additively designed, and a 1mm machining allowance is added to the entire exterior to form a 3D printed hollow blade blank part model M2. Then, a spiral crystal selector structure three-dimensional model X1 is designed at the bottom center of the model M2, and the three-dimensional model Y1 is combined to form a 3D printed hollow blade model Y1, wherein the spiral crystal selector has a pitch of 25mm, a spiral diameter of 20mm, a wire diameter of 5mm, a rise angle of 45°, and a spiral turn of 1 turn, so that the main orientation of the obtained single crystal is in the

[001] direction. The model Y1 is sliced, and the slice layer thickness is 0.04mm to obtain the 3D printed hollow blade data parameter Y2, and the data parameter Y2 is imported into the electron beam 3D printer.

[0062] (7) Set up the electron beam 3D printer to carry out printing preparation and processing: evacuate the vacuum to ≤0.3Pa, set the preheating temperature parameters to 1030℃, and the insulation time to 30min; set the part entity printing parameters: electron beam current 46mA, scanning speed 6.5m / s; until printing is completed, the vacuum is naturally cooled to room temperature with the furnace.

[0063] (8) Due to the long-term preheating and sintering of the powder at high temperature, the powder has been in a pseudo-sintering state, forming a sintered brick, and the parts are in the sintered brick. The sintered brick is transported to the electron beam powder recovery equipment, and 1 kg of Ni-based alloy powder F2 is pre-placed in the equipment. The equipment is similar to a sandblasting machine. After the equipment door is closed, the spraying is started, and the Ni-based alloy powder F2 is sprayed out from the spray gun at high pressure, spraying the sintered brick, gradually breaking up the brick body to form the recovered Ni-based alloy powder F3, and finally taking out the Ni-based alloy hollow blade blank Z1.

[0064] (9) The Ni-based alloy hollow blade blank Z1 is placed in a high vacuum heat treatment furnace for solution treatment and aging treatment. The parameters are: the pressure in the furnace is pumped down to 10 -3 Pa, and then set the heat treatment temperature and time parameters, starting from 20℃ (room temperature), heating to 1000℃ at a heating rate of 10℃ / min, heating to 1300±5℃ at a heating rate of 5℃ / min, and then heating to 1350±5℃ at a heating rate of 2.5℃ / min, and keeping the temperature for 18h. After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s; then, starting from 50°C (furnace temperature), the temperature is increased to 900°C at a heating rate of 10°C / min, and the temperature is kept for 12-30h. After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s. The furnace door is opened, and the Ni-based alloy hollow blade blank Z2 that has been solution and aging treated is taken out.

[0065] (10) According to the blade design drawing, the Ni-based alloy hollow blade blank Z2 after solid solution and aging treatment was machined to remove the surface machining allowance. The cutting speed was 800 r / min, the feed rate was 400 mm / min, and the cutting width was 5 mm to obtain the machined Ni-based alloy hollow blade Z3.

[0066] (11) Plasma polishing was performed on the machined Ni-based alloy hollow blade Z3 to remove the defective layer on the blade surface. The plasma liquid formula was ammonium sulfate: sodium citrate: distilled water = 3:1.5:100, the polishing temperature was 75°C, the polishing voltage was 290V, and the polishing time was 3min. Finally, a Ni-based single crystal hollow blade Z4 with a surface roughness of Ra0.3μm and dimensional accuracy that met the requirements of the drawing was obtained.

[0067] Using the same powder and process as the Ni-based single crystal hollow blade, the same furnace sample was processed into a Ni-based single crystal mechanical tensile specimen (R7), and a high-temperature creep test was carried out. The results showed that the Ni-based single crystal sample had a creep stress of 137MPa and a creep life of 1074h at 1100°C. Compared with the traditional Ni-based single crystal material (137MPa and 721h), the creep life was increased by more than 49%, and the performance was significantly improved. The yield rate of the Ni-based single crystal hollow blade exceeded 90%, which was higher than the traditional processing yield rate (about 10%). Therefore, the high-temperature performance of the Ni-based single crystal hollow blade prepared by the present invention is much better than the traditional processing scheme, which is conducive to promoting the promotion and application of Ni-based single crystal materials / parts.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a hollow blade of a Ni-based single crystal high-temperature alloy by electron beam selective 3D printing, characterized in that: The steps include: Step 1: Place the proportioned alloy raw materials into a water-cooled copper crucible induction melting furnace for smelting, and prepare a Ni-based alloy rod B2 through casting and machining; Step 2: using a plasma rotating electrode method to prepare a spherical Ni-based alloy powder F1 from the Ni-based alloy rod B2; Step 3: Wash and sieve the spherical Ni-based alloy powder F1 to obtain the spherical Ni-based alloy powder F2, and load the spherical Ni-based alloy powder F2 into the powder storage box of the electron beam 3D printer; Step 4: Design the hollow blade model with additive materials, set the printer parameters, and perform electron beam selected area 3D printing; Step 5: After the electron beam selected area 3D printing is completed, the powder is recovered to obtain a Ni-based alloy hollow blade blank Z1; Step 6: performing solid solution and aging treatment on the Ni-based alloy hollow blade blank Z1 to obtain a Ni-based alloy hollow blade blank Z2; Step 7: machining the Ni-based alloy hollow blade blank Z2 to obtain a Ni-based alloy hollow blade Z3; Step 8: Plasma polishing is performed on the Ni-based alloy hollow blade Z3 to obtain a Ni-based single crystal hollow blade.

2. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step 1, the alloy raw materials are all pure metal raw materials with a purity of 99.999%, and contain the following components in parts by weight: Cr: 2.0-4.6%; Co: 0.2~16.5%; Mo: 1.0~3.9%; W: 5.0~6.0%; Ta: 5.0~8.25%; Al: 5.5~6.0%; Re: 4.0~6.9%; Ru: 2.0~6.0%, Hf: 0.1%, and the rest is Ni.

3. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step 1, the vacuum degree is less than 10 -3 The master alloy is melted in a water-cooled copper crucible induction suspension melting furnace at 1550-1750°C for 5-15 min. The alloy composition is homogenized after 1 to 5 meltings. CaO is used to make a melt shell for casting into a Ni-based alloy rod B1. The size of the Ni-based alloy rod B1 is 71×290 mm. After machining, it is made into a Ni-based alloy rod B2 with a size of 70×285 mm and a surface roughness Ra<0.8 μm.

4. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step 2, the plasma rotating electrode method uses a plasma rotating electrode powder making device, the Ni-based alloy rod B2 is loaded into the plasma rotating electrode powder making device, the electrode speed is set to 16000-25000r / min, the plasma arc current is 1500-2600A, and the Ni-based alloy powder is prepared under a vacuum state. After the preparation is completed, spherical Ni-based alloy powder F1 with a particle size distribution of 50 to 175μm is obtained through screening.

5. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step three, the Ni-based alloy powder F1 is loaded into a vacuum plasma cleaning device, a mixed gas medium of H2:Ar2=1:1 is selected, the power is set to 210-270W, and the time is 1-10 minutes to perform argon ion cleaning; after the cleaning is completed, the Ni-based alloy powder F1 is sieved to obtain a spherical Ni-based alloy powder F2 with a particle size distribution of 45 to 155 μm.

6. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step 4, the method of additive design is: adding a 0.5-1.5 mm machining allowance to the entire exterior of the hollow blade three-dimensional model M1 to form a 3D printed hollow blade blank part model M2, designing a spiral crystal selector structure three-dimensional model X1 at the bottom center of the 3D printed hollow blade blank part model M2, and combining to form a 3D printed hollow blade model Y1, wherein the spiral crystal selector has a pitch of 20-35 mm, a spiral diameter of 10-30 mm, a wire diameter of 4-6 mm, a rise angle of 35-70°, and a spiral number of 1-3 turns, so that the main orientation of the obtained single crystal is in the [001] direction; slicing the 3D printed hollow blade model Y1, with a slice layer thickness of 0.03-0.3 mm, obtaining a 3D printed hollow blade data parameter Y2, and importing the 3D printed hollow blade data parameter Y2 into an electron beam 3D printer; The printer parameter settings include: vacuuming to ≤0.3Pa, preheating temperature parameters set to 1000~1300℃, and holding time of 30min; the part entity printing parameters are set to: electron beam current of 25~48mA, scanning speed of 5-15m / s; after printing is completed, the vacuum is naturally cooled to room temperature with the furnace.

7. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step five, when the powder is preheated and sintered at high temperature for a long time and presents a pseudo-sintered state and forms a sintered brick, the parts are in the sintered brick. The sintered brick is transported to the electron beam powder recovery equipment, and 1 kg of Ni-based alloy powder F2 is pre-placed in the powder recovery equipment. After the equipment door is closed, the spraying is started, and the Ni-based alloy powder F2 is sprayed out from the spray gun at high pressure to spray the sintered brick, gradually breaking up the brick body to form recovered Ni-based alloy powder F3. After the spraying is completed, the Ni-based alloy hollow blade blank Z1 is taken out.

8. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step six, the Ni-based alloy hollow blade blank Z1 is placed in a high vacuum heat treatment furnace for solution treatment and aging treatment, which specifically includes the following steps: The pressure in the high vacuum heat treatment furnace is pumped down to 10 -3 Pa, heat treatment: starting from room temperature of 20℃, heating to 1000℃ at a heating rate of 10℃ / min, then heating to 1300±5℃ at a heating rate of 5℃ / min on the basis of 1000℃, then heating to 1350±5℃ at a heating rate of 2.5℃ / min on the basis of 1300±5℃, and keeping at 1350±5℃ for 10h~20h; After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s; thereafter, starting from a furnace temperature of 50°C, the temperature is increased to 870-920°C at a heating rate of 10°C / min, and the temperature is kept for 12-30h. After the insulation is completed, 99.999% high-purity argon is slowly filled into the furnace, and the furnace fan is started. The argon filling is stopped when the furnace pressure reaches 90kPa, and the furnace is cooled to 50°C at a cooling rate of 2.5°C / s. The furnace door is opened, and the Ni-based alloy hollow blade blank Z2 that has undergone solid solution and aging treatment is taken out.

9. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step seven, the machining cutting speed is 400-1600 r / min, the feed rate is 200-1200 mm / min, and the cutting width is 4-10 mm to remove the surface machining allowance.

10. The method for manufacturing a hollow Ni-based single crystal high-temperature alloy blade by electron beam selective 3D printing according to claim 1, characterized in that: In the step eight, the polishing temperature of the plasma polishing treatment is 75°C, the polishing voltage is 250-350V, the polishing time is 2-10min, and the plasma polishing treatment is performed using a plasma liquid, the plasma liquid is composed of ammonium sulfate, sodium citrate and distilled water, ammonium sulfate: sodium citrate: distilled water = (1-5): (0.5-2.5): 100; the surface roughness Ra of the Ni-based single crystal hollow blade Z4 is <0.8μm.

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